Disazo dyes and process of making same.



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AUGUST LEOIPOLD LASKA, OF OFFENBACH-ON-THE-MAIN, GERMANY, ASSIGNOR TO THE CORPORATION OF CHEMISCHE FABRIK GRIESI-IEIM ELEKTRON, OF FRANKFURT-ON- THE-MAIN, GERMANY.

DISAZO DYES AND PROCESS OF MAKING SAME.

No Drawing.

Specification of Letters Patent.

Application filed February 9, 1911.

To all whom it may concern:

Be it known that I, Anous'r IJIGOPOLI) LASKA, doctor of philosophy, chemist, a subject of the German Emperor, and resident of Otfenbach-on-the-Main, in the Grand Duchy of Hessen, Germany, with the post office address Dreieichring No. 18, have invented new and useful In'iprovemcnts in Disazo Dyes and Processes of ltllaking the Same, of which the following is a specification.

I have found. that reddish yellow to orange red disazo dyestuffs can be obtained by combining the tetrazo compound of orthodichlorobcnzidin (NH :Cl:1 :2) with two molecular proportions of 1-aryl-3- methyl-5-pyrazolone. The thus obtained dyestuffs may be used preferably in the manufacture of pigment colors, as they are insoluble in water and oil.

The new disazo dyestuffs correspond to the general formula:

wherein P stands for the radical dichlorodt phenyl (N:N :Cl-1z2) and X for 1- aryl-3-methylS-pyrazolone.

The color lakes obtained from the new dyestuffs are very fast to light and have a great covering power.

The following example will serve to illustrate the nature of my invention; parts being by weight.

Example: 25.3 parts of ortho-diehlorobenzidin are dissolved in 1000 parts of hot water and 85 parts of hydrochloric acid. The solution is strained if necessary and diazotized after cooling with ice by means of 14.4 parts of sodium nitrite. The diazo solution is poured into a solution of 38 parts of methylphenylpyrazolone in 1000 parts of water and 30 parts of hydrochloric acid 20 Be. A solution of 140 parts of sodium acetate is added and the mixture stirred till the formation of dyestutl' is completed. The dyestu'tf is separated during the cmubination in shape of orange flakes. It is filtered off, washed out and used preferably in form of a paste. The dycstutf is in dry state a bright orange-red, powder, insoluble in water, soluble in eoi'icentratcd sulfuric acid with red color. It can be trans'torn'ied into color lakes of orange tints in the usual manner. These lakes show an excellent fastness against water and oil.

Of course the preparation of the dycstutt' can be performed in presence of a substratum also.

The formation of dyestutli's with homologues and products of substitution of methyl-phenyl-pyrazolone may be carried out in the same manner.

The products substituted in orthoposition to the pyrazohme-nitrogcu atom show more yellowish tint.

Now what T claim and desire to secure by Letters Patent is the following:

1. The process for the production of disaxo dyestu'tls specially suitable for the preparatio-n of pigment colors, consisting in combining the tetrazo compound of ortho-dichlorobenzidin (NH :Cl :1 :2) with two molecular proportions of 1-aryl-3 methyl-5- pyrazolonc.

2. As new articles the disazo dyestuffs, which dyestutl's arc in dry state yellow red to red powders, entirely insoluble in water soluble in concentrated sulfuric acid with yellow-red to red color and yielding upon reduction with stannous chlorid and hydrochloric acid o-dichlorobenzidin and -t-amino- 1-aryl-hnethyl-5-pyrazolone; which dyestull's can easily be transformed in color ltlliOS of reddish yellow to orange red tints, being very fast against oil and water.

3. The process for the production of a new disazo dyestutt' specially suitable for the preparation of pigment colors, consisting in combining the tetrazo compound of orthodichloro-benzidin with two molecular proportions of '1.-phenyl-3-mctl1yl'5-pyrazotone.

4. As a new article the disazo dyestutl', which dyestutt is in dry state a bright orange-red powder, entirely insoluble in water, soluble in concentrated sulfuric acid with red color yielding upon reduction with stannous chlorid and hydrochloric acid 0- as my invention, I have signed my name in dichlorobenzidin and 4-amino-1-pheny1-3- presence of two Witnesses, this twenty-sixth methyl-5-pyrazo1one; Which dyestufi can day of January 1911.

easily be transformed in a color lake of AUGUST LEOPOLD LASKA. orange tint, being very fast against oil and WVitnesses: Water. HERMANN WEIL,

In testimony, that I claim the foregoing ROBERT BI'iHL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

